| 摘要 |
The pearl has a nucleus (1) that is surrounded by growth layers (2,3) and an outer skin (4) that reflects light. The outer layer of the pearl is cut to obtain a flat surface (5) below the skin. The cut surface is polished to allow light to penetrate inside the pearl. The pearl can be cut with several facets that are at different depths and cut through different layers so that the facets show different colours.
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